EFFECT OF LOW TEMPERATURE, SODIUM NITRITE, SODIUM CHLORIDE, AND FORMALDEHYDE ON THE APYRASE SYSTEM OF THE MUSCULAR TISSUE^a

Abstract

One of the enzyme systems most essential for living organisms is the apyrase system which hydrolyzes adenosine triphosphate ( ATP) . The ATP splitting mediates the phenomenon of movement, e.g. muscle contraction, constriction of the cell plasma on cell separation, separation of the chromosome deposits in the anaphase of the mitose, etc. (13, 34, 35). This enzyme system seems to be essential for the transfer of energy obtained from metabolism to living structures (30,27). It has been found also in bacteria ( 5 ) and viruses (10).The reactions on which muscular contraction are based can be regarded as going on in two stages: the first step, producing about 10,000 cal/mole ATP (30, 17) and an inorganic phosphate, leads to adenosine diphosphate. I n the skeleton musculature of the vertebrates this reaction is catalyzed mainly by the myosin-adenosine triphosphatase bound to the actomyosin, and partially by the magnesium-activated adenosine triphosphatase of Kielley and Meyerhof (13). In the second step the adenosine diphosphate is dismutated to adenosine monophosphate and -triphosphate by the enzyme myokinase. I n the physiological pH-range between 6 and 7 the musculature can be considered as a specific apyrase system (28,19).The apyrase activity can easily be measured in cross-striated muscle tissue. The time-reaction curve for the ATP split by the musculature shows two different parts, each of which can be considered in approximation as a first order reaction (21).When ATP is added to a suspension of cross-striated muscle fibers in a suitable medium an irreversible contraction of the fragments is obtained (16) ; this can be measured under the microscope (22,23,24).Extensive investigation of the apyrase system has revealed a close correlation between contraction and ATP splitting (36). It was evident that the two methods for measuring enzyme activity and contractility might be used to investigate the effect of adjuncts and freezer storage on foods. I n our opinion a food adjunct cannot be considered physiologically harmless if small quantities of it inhibit the apyrase system of fish or mammal muscular tissue irreversibly.This investigation deals mainly with the effect of sodium nitrite, sodium chloride, and formaldehyde on the apyrase system of white muscle of carp. I n order to support some views of general importance results of freezer storage experiments and artificial ripening of meat are briefly discussed too.

Reaction of Cod Actomyosin with Linoleic and Linolenic Acids

“…Similar correlations have been found in other species of fish during frozen storage (Dyer, 1951 ;Heen, 1954 ;Nikkila and Linko, 1954). Although actomyosin denaturation may be measured by several methods (Comlell, 1960a ;Partmann, 1957 ;Sawant and Magar, 1961), the criterion of denaturation that is best correlated with textural changes in fish muscle is loss of extractability.…”

Contractibility of Muscle Fibres as a Possible Aid to Judging Textural Changes in Frozen Meats and Fish

“…About 17 years ago, we found it highly fascinating that fibre fragments of a homogenate obtained from frozen muscle contract upon addition of adenosine triphosphate in a suitable medium (Partmann, 1955a). Fish muscle samples stored at -3.5"C for about one month showed a considerable decrease in ATPase activity and contractibility (Partmann, 1957). At that time, the method used for testing the contractibility was to measure, under the microscope, the change in length of the fibre fragments of a muscle homogenate after addition of ATP.…”

The acid-soluble nucleotides of codling (Gadus callarias) muscle

“…Tarr (1950) and Fujimaki & Kojo (1953) investigated a number of Pacific Ocean species by the fractionation of extracts with barium, and Partmann (1954) measured the adenosine 5'-triphosphate contents of tench and pike muscles. Steinbach (1949), Davison & Richards (1954) and Partmann (1954Partmann ( , 1957Partmann ( , 1958 have examined the apyrase activities occurring in fish muscle under different conditions. In preliminary communications (Jones & Murray, 1957;Jones, 1958) we described separations of the major constituents of the nucleotide fraction in codling muscle during exercise and after death.…”